Baader T2 Delrin Spacer Ring Set

[m37]

Seem to do the job with a couple of caveats:

1. They are not marked for thickness in any way and come all in one plastic bag. I found that if you lay a pair next to each other and use a small thin implement slid across from one to the other you can more or less judge whether they are the same or slightly different thicknesses and thereby deduce the range. Luckily I needed the thickest one which seemed relatively easy to spot. Good luck sorting a 0.4mm spacer from a 0.6mm spacer by eye though.
2. Not sure if it is my particular FR that is a bit off on tolerances or the spacers themselves, but I virtually dislocated my shoulder trying to get the (I think) thickest spacer on. In the end I had to employ a thin plastic ballpoint pen casing to 'persuade' it on without risking my FR thread. Pen is no longer in service, although for an imager to complain about the cost of a biro is clearly absurd!!! It's not like I can just steal them from work or anything.
3. I will probably need a sub-miniature car jack, dentist drill or laser should it need to come off again. Seriously though, it would have to be cut off with a scalpel blade or similar then discarded.
4. I suspect the difficulty in deploying these stems from the robustness which is essential for maintaining an accurate spacing even when tightened

Chris